Tracking the Opioid Drug Overdose Epidemic in King County, Washington Using an Improved Methodology for Certifying Heroin Related Deaths

Guidelines of the National Association of Medical Examiners recommend that death certificates of overdose deaths list specific drugs. While this is important in tracking the national opioid drug overdose epidemic, differentiating heroin from morphine as the source drug remains problematic. To distinguish the two, a specific methodology was developed for death certification based on a combination of toxicology testing and scene investigation. This study evaluates the methodology in assessing the contribution of heroin. In two decades in King County, there were 3369 opioid drug overdose deaths, ranging from 139 in 1995 to 233 in 2014. In the 1990's, opioid overdose deaths were predominantly due to heroin; deaths due to prescription opioids were relatively uncommon. This trend reversed around 2003 with overdose deaths due to heroin declining and those due to prescription opioids increasing. The trend again reversed around 2012 with resurgence of heroin and declining deaths due to prescription opioids. Before the specific methodology was employed, it was known that heroin was the predominant opioid, but the summary data did not differentiate morphine and heroin. After adopting the methodology in 2004, the data reasonably tracked the contribution of heroin: out of 2125 opioid deaths, 34% were due to heroin, ranging from 14% in 2009 to 65% in 2014. The results of this study show an overall increase in opioid deaths and an inverse relationship between heroin and the prescription opioids. Furthermore, the specific methodology for certifying heroin deaths greatly improves accuracy in tracking opioid overdose deaths.